This invention relates to wire guides which may be used for placement of catheters.
One application for which such wire guides are used is the percutaneous placement of a catheter into the vascular system. The procedure involves penetrating an organ, such as a vein or the like, with a needle. The wire guide is then passed through the needle into the organ. The needle is then withdrawn over the wire guide, leaving the wire guide in place in the organ. A catheter is then slid over the wire guide into the organ and further guided by the wire guide through the organ. Such a wire guide can be used, for example, to position a catheter at difficult to reach locations in or around the heart or the like.
Wire guides have heretofore been provided to facilitate the insertion of a catheter into an organ, such as a vein, and further to facilitate the guidance of a catheter through an organ to various locations in a body. Certain prior art wire guides have a coil spring throughout its entire length of the guide and therefore are susceptible to breakage. In addition, use of some prior art wire guides create friction between the coils of the spring and the inner surface of the organ.
In order to overcome such problems, wire guides were developed having a plastic outside surface. Other wire guides have been developed including a hydrophilic coating on the outside surface in order to reduce friction between the outer surface of the wire guide and the inner surface of the organ and further to reduce the likelihood of breakage of the wire guide while in the organ. As regards prior art wire guides having a hydrophilic coating on their outside surface, such coating extends over the entire proximal portion of the wire guide making it difficult for the operator to grip and control the wire guide.